1. Field of the Invention
The preset invention relates to a workpiece conveying device having a robot for conveying a workpiece that has a burr, such as a hot forged part.
2. Description of the Related Art
When a material such as a metal that has a forged part is manufactured by hot-forging or cold-forging, a plate-like burr or excess thickness portion may be formed on the forged part. When the product that has a burr (or a workpiece) is conveyed to a next process stage, it is necessary to consider the existence of the burr.
As relevant prior art documents, JP H05-131240 A discloses a robot 1 configured to grip an outer edge of a burr 22 by moving grip claws 8 at a frond end of a robot arm 4, based on data obtained by image-processing an image which is obtained by capturing a formed article 20 on a relay table 11 by means of a camera 5.
In JP H05-131240 A, the forged article with the burr is detected by means of the camera from above, and the burr is gripped so as to convey the forged article. Concretely, a boundary between the burr and a main body of the forged article is detected by the camera so as to correct the position of the grip claws. However, it is actually difficult to correctly detect the boundary between the burr and the main body based on an image obtained by the camera, and the grip claws may fail to grip the article or may damage the main body.